Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/loader/DocumentThreadableLoader.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 45 matching lines @@
 {
     // The loader will be deleted as soon as this function exits.
     RefPtr<DocumentThreadableLoader> loader = adoptRef(new DocumentThreadableLoader(document, &client, LoadSynchronously, request, options));
     ASSERT(loader->hasOneRef());
 }
 
 PassRefPtr<DocumentThreadableLoader> DocumentThreadableLoader::create(Document* document, ThreadableLoaderClient* client, const ResourceRequest& request, const ThreadableLoaderOptions& options)
 {
     RefPtr<DocumentThreadableLoader> loader = adoptRef(new DocumentThreadableLoader(document, client, LoadAsynchronously, request, options));
     if (!loader->resource())
-        loader = 0;
+        loader = nullptr;
     return loader.release();
 }
 
 DocumentThreadableLoader::DocumentThreadableLoader(Document* document, ThreadableLoaderClient* client, BlockingBehavior blockingBehavior, const ResourceRequest& request, const ThreadableLoaderOptions& options)
     : m_client(client)
     , m_document(document)
     , m_options(options)
     , m_sameOriginRequest(securityOrigin()->canRequest(request.url()))
     , m_simpleRequest(true)
     , m_async(blockingBehavior == LoadAsynchronously)
@@ skipping 378 matching lines @@
         return true;
     return m_document->contentSecurityPolicy()->allowConnectToSource(url);
 }
 
 SecurityOrigin* DocumentThreadableLoader::securityOrigin() const
 {
     return m_options.securityOrigin ? m_options.securityOrigin.get() : m_document->securityOrigin();
 }
 
 } // namespace WebCore